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1
6 December 2012
Challenge the future
DelftUniversity ofTechnology
CT4485 Wastewater Treatment
Lecture 4c: Anaerobic Reactor TechnologiesProf.dr.ir. Jules van Lier
2Anaerobic Wastewater Treatment
Sludge digestion
1.septic tank
a.height of liquidb.> 7.5 cmc.> 30 cmd.40% of liquid heighte.2/3 of Lf. 1/3 of L
sludge
scum layer
Donald Cameron, 1895 (UK)
2
3Anaerobic Wastewater Treatment
Sludge digestion
2. Imhoff tank
A. effluentB. sludge feedC. settlingD. settled sludgeE. sludge digestingF. sludge discharge pipe
Karl Imhoff, 1905 (Germany)
4Anaerobic Wastewater Treatment
Sludge digestion & Wastewater treatment
3. Clarigester
A. sludge feedB. effluentC. scum dischargeD. scum break offE. bottom scraperF. sludge discharge pipe
Stander, 1950 (South Africa)
3
5Anaerobic Wastewater Treatment
1930’s
Buswell
IndustrialWastes
Wastewater Treatment
6Anaerobic Wastewater Treatment
1955, Shroepfer, USA
Schroepfer
Contact process
Wastewater Treatment
4
7Anaerobic Wastewater Treatment
methanereactor
Flocculator or degasifier Clarifier
influent effluent
recycle sludgeexcess sludge
Contact Process (CP)
8Anaerobic Wastewater Treatment
basic principles:
• complete mixing in the digester in order to achieve good contact
between sludge and wastewater
• sludge recycling (flow rate generally 80-100 % of the influent flow
rate) in order to maintain a high sludge content in the digester
=> high organic removal efficiency stable operation
The Anaerobic Contact Process
5
9Anaerobic Wastewater Treatment
type of waste water
sludge loading(kg COD ·
kg-1 VSS · d-1)
load(kg COD ·
m-3 · d-1)
reactor volume(m3)
COD removal
efficiency (%)
sugar factory
distillery
citric acid
yeast factory
dairy
green vegetable cannery
pectin factory
starch factory
meat processing works
1.3 - 2.0
0.17 - 0.24
0.16 - 0.29
0.24 - 0.37
0.13
0.11 - 0.28
0.03 - 0.22
1.4
0.5 - 1.1
0.6 - 12.9
1.5 - 2.5
1.3 - 4.0
2.8 - 3.9
0.88
2.0 - 4.2
1.7 - 5.3
3.6
0.8 - 4.8
2100 - 16000
300 - 1890
10000
1900
84
5000
3000 - 3618
900
2670 - 7117
90 - 95
90 - 98
75 - 83
77 - 82
-
90 - 95
88 - 93
65
88 - 95
The anaerobic contact process
10Anaerobic Wastewater Treatment
1970s, Gatze Lettinga, The Netherlands
Lettinga
UASB
Wastewater Treatment: UASB
6
11Anaerobic Wastewater Treatment
Development of “high-rate” anaerobic treatment systems
Completely mixed
(Bio)gas
influent effluent
Relative capacity: 1
Physical retention
Relative capacity: 5
Immobilised biomass
Relative capacity: 25
12Anaerobic Wastewater Treatment
Early full-scale UASB for sugar mill effluent (CSM,1976)
7
13Anaerobic Wastewater Treatment
Anaerobic Granular Sludge
Sorry guys.., I only appear when Dutch
men are around…!
14Anaerobic Wastewater Treatment
Expanded Granular Sludge Bed (EGSB) Reactors
Main Features- High upflow velocities (> 8 m/h)- High concentration of bio-catalyst- Extreme loading rates (20-40 kg/m3.d) - Virtually no mass transfer limitation - Very small footprint
Application:- cost effective alternative for UASB (2-3 times
higher load)- Cold wastewaters (< 20°C)- Dilute wastewaters ( < 1 g COD/l)- Presence of degradable toxic compounds- LCFA containing wastewaters- Wastewaters with foaming problems in UASB
Biogas
Effluent
Influent
Granularsludge
Effective use of granular sludge !!
8
15Anaerobic Wastewater Treatment
Completely mixed
(Bio)gas
influent effluent
Relative capacity: 1
Physical retention
Relative capacity: 5
Immobilised biomass
Relative capacity: 25
Enhanced contact
Relative capacity: 75
Development of “high-rate” anaerobic treatment systems
16Anaerobic Wastewater Treatment
Influent
Sludge bed
Settler
EffluentBiogas
Sludge blanket
2 2
1 1
3 32
1. Sludge/biomass inlet2. Gas baffle plates3. Return settled sludge
From UASB to EGSB
Sludge bed
Influent
Effluent
Biogas
2
1
1. Sludge/water mixture2. Settled sludge
Re
cycle
Biothane Systems International
9
17Anaerobic Wastewater Treatment
Application of Multi-layer settling system
Polypropylene settlers
Less PP per m2/ No tropical hardwood
18Anaerobic Wastewater Treatment
Developments – Technical/Technological
Biopaq® - UASBBiopaq® - IC
10
19Anaerobic Wastewater Treatment
Developments – Technical/Technological
Increasing diameter of Biopaq® - IC
20Anaerobic Wastewater Treatment
Developments – Technical/Technological
2008 : 15 m
1987 : 2,8 m
100 tpd CODper reactor
11
21Anaerobic Wastewater Treatment
Developments – Technical/Technological
1989 : 6 x Ø 3,2 m
1996 : 1 x Ø 8 m
22Anaerobic Wastewater Treatment
Full scale AWWT at beer brewery
Beer, NL Heineken, Den BoschUASB
IC
Paper, China
12
23Anaerobic Wastewater Treatment
Chemical Wastewater TreatmentCOD: 40 kg/m3, of which: - Formaldehyde 20 kg/m3
- Methanol 10 kg/m3
Possible to treat with a UASB??
24Anaerobic Wastewater Treatment
Fe + micro
Flare
5 m3/h
Conditioning
tank20 m3
Buffertank150 m3
Biobed®
reactor275 m3
5 m3/h 150 m3/h
145 m3/h
120 m3/d
Caustic
Yeast extr.
Macro nut.
Waste water To Carrousel®
Amended process design to prevent toxicity in anaerobic stage
Chemical Wastewater Treatment
98% efficiency17 kg COD/m3.day
Influent : recycle ratio = 1 : 30 !!
Total COD: 40 g/lFormaldehyde: 20 g/l
13
25Anaerobic Wastewater Treatment
Influent
Effluent
BiogasUpflow Anaerobic Attached Fixed Film Expanded Bed (EB)
Attached Growth Anaerobic Fluidised Bed (FB)
Fluidized Bed Systems
26Anaerobic Wastewater Treatment
FB reactors rebuilt to EGSB reactors at DSM-yeast factory, Delft
14
27Anaerobic Wastewater Treatment
Anaerobic Attached Growth Processes
28Anaerobic Wastewater Treatment
Upflow Anaerobic Filters (UAF)
Downflow Stationary Fixed Film (DSFF)
Influent
Effluent
Recycle
Biogas
Influent
Effluent
Recycle
Biogas
Anaerobic Filter Systems (1)
15
29Anaerobic Wastewater Treatment
Upflow Anaerobic Filter (UAF)
based on:- attachment of a biofilm to a solid (stationary) carrier material- sedimentation and entrapment of sludge particles between the
interstices of the packing material- formation of well settling sludge aggregates
Major disadvantage- difficult to realise required contact between sludge and wastewater- applicable loads are relatively low, I.e. generally below 10 kgCOD/m3.day
Anaerobic Filter Systems (2)
30Anaerobic Wastewater Treatment
Downflow Stationary Fixed Film (DSFF)Attached Anaerobic Film (AFF)
Sludge retention based on:Attachment of biomass to the packing.(sludge retention is relatively low, because hardly any suspended material retained)
- generally no channelling problems- low loading potentials
Anaerobic Filter Systems (3)
16
31Anaerobic Wastewater Treatment
Historically applied anaerobic processes(1981 – 2007 (Jan.) N= 2266)
(Granular) sludge bed based: 77%
IC15%
UASB50%
* 1%FB 2%
HYBR 3%
LAG 4%
CSTR 7%
AF 6%
EGSB 12%
* References with incomplete data (1%)Source: Worldref. 04-2007
32Anaerobic Wastewater Treatment
Currently Applied Anaerobic Processes(2002 – 2007 (Jan.), N= 610)
* References with incomplete data (1%)Source: Worldref. 04-2007
(Granular) sludge bed based: 89%
Expanded Bed Reactors: 55%
IC33%
* 1%FB 2%
HYBR 2%
LAG 1%CSTR 4%
AF 1%
EGSB 22%
UASB34%
17
33Anaerobic Wastewater Treatment
Full Scale Expanded Bed versus UASB Systems
UASB
Expanded Bed (EGSB, IC, FB)
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
1980 1985 1990 1995 2000 2005 2010
Year
Per
cen
tag
e o
f ye
arly
pro
ject
s
UASB
HIGH RATE (EGSB+FB+IC)
34Anaerobic Wastewater Treatment
Gas
Permeate
Gas
Permeate
Gas
Permeate
Novel development: Aerobic MBR applications / potential Anaerobic homologues
18
35Anaerobic Wastewater Treatment
permeate
biogas injection
wastewater
over-flowpump
P
pressuresensor pump
gas flow-meter
biogasAD under Extreme Conditions
David Jeison (2005)
AD under Extreme Conditions
David Jeison (2005)
Anaerobic Membrane Bioreactor (AMBR)
Fouling control: back-flushing, flow stoppage, biogas recirculation (also for mixing).
36Anaerobic Wastewater Treatment
Operational performance submerged AnMBR
0
10
20
30
40
50
0 100 200 300
Time (d)
OL
R (
kgC
OD
/m3d
)
0
20
40
60
80
100
CO
D r
emo
val (
%)
OLR COD Removal
0
10
20
30
40
50
0 100 200 300
Time (d)
So
lids
(g/L
)
TSS VSS
Mesophilic conditions, VFA-fed reactor
19
37Anaerobic Wastewater Treatment
0
5
10
15
20
25
0 50 100 150 200 250
Time (d)
Cri
tica
l flu
x (L
/m2h
)
R1: thermophiliccompletely acidifiedR3: mesophiliccompletely acidified
Thermophilic
Mesophilic
Mesophilic Thermophilic
Flux determining factors in anaerobic MBRs
Smaller particle size
Particledeposition
High shear rate
The shear rate dilemma…
(Jeison and van Lier, 2008)
38Anaerobic Wastewater Treatment
• high retention of viable sludge in the reactor
• sufficient contact between viable biomass and waste water
• high reaction rates and absence of serious transport limitations of
substrate and metabolic end products
• sufficiently adapted and/or acclimatised viable biomass
• prevalence of favourable environmental conditions for all required
organisms inside the reactor under all imposed operational
conditions
High Rate Anaerobic Reactor Systems
20
39Anaerobic Wastewater Treatment
Bacterial attachment on non-fixed carriers
e.g. FB (Fluidised Bed) reactors
Bacterial attachment on fixed support materials
e.g. Anaerobic filters
Auto immobilisation / granulation
e.g. UASB (Upflow Anaerobic Sludge Bed) reactors
Sludge settling and membrane filtratione.g. CP (Contact Process) reactors
AMBR (Anaerobic membrane bioreactors)
AttachedFilm
Principles of Sludge Retention in High-Rate Reactors
Sludge Bed
Separation